World 1-1 (Super Mario Maker for Nintendo 3DS)
From the Super Mario Wiki, the Mario encyclopedia
This level is a near exact replica of World 1-1 from Super Mario Bros., and is a much more accurate remake compared to 1-1 Remix (Ground), the eleventh sample course of Super Mario Maker (Wii U). Even such minor details as the bushes in the background scenery have been replicated.
There is one somewhat major difference in this remake, however. In the underground bonus area, it's possible to return to the place where the hidden 1-Up Mushroom is found by going through the Warp Pipe on the ceiling, though this takes a skillful jump and requires being in the Super Mario (or Fire Mario) form.